In the field of optical fibers to be coupled to opto-electronic and/or photonic integrated elements, properly aligning a fiber end piece to a respective integrated element, such as a photo diode, a VCSEL or another opto-electronic active element, or to a photonic element comprising a photonic integrated circuit impacts optical performance. In a fiber coupling device comprising at least one opto-electronic and/or photonic chip, the optical connection between the opto-electronic and/or photonic element, i.e. the integrated element, and the fiber end piece must be realized in a perfectly aligned manner for enabling optimum coupling efficiency with maximum intensity of radiation being transmissible between the optical fiber and the light-detecting or light-emitting element. Any positional offset or mismatch between the integrated element and the end piece of the optical fiber will decrease coupling efficiency and will deteriorate signal transmission. These issues are even more concern for signal transmission with data rates of about 20 GB/s or beyond, high-speed signal transmission thus requires precise alignment of fiber end pieces.
In order to ensure maximum signal integrity, there are techniques for active alignment which involve the measurement of the transmitted signal intensity during mounting of the fiber end piece to the integrated element. More efficient techniques use self-alignment between the fiber end piece and the integrated element. For these techniques, optical fibers are used which are cleaved and polished at the respective fiber end so as to have a planar, flat exit and/or entrance surface essentially perpendicular to the axial direction of the fiber along which light propagation occurs. Such fiber end-pieces are, for example, glued to respective support structures on the opto-electronic chip which support structures may comprise mirrors for deflecting the direction of propagation by 90°.